Intra-articular injections of expanded mesenchymal stem cells with and without addition of platelet-rich plasma are safe and effective for knee osteoarthritis

To compare the effectiveness and safety of intra-articular injections of autologous expanded mesenchymal stromal stem cells alone (MSCs), or in combination with platelet-rich plasma (MSCs + PRP), in patients with knee osteoarthritis. Eighteen patients (57.6 ± 9.6 years) with radiographic symptomatic knee osteoarthritis (Dejour grades II–IV) were randomized to receive intra-articular injections of MSCs (n = 9) or MSCs + PRP (n = 9). Injections were performed 2–3 weeks after bone marrow aspiration (± 80–100 ml) which was obtained from both posterior iliac crests. The Knee Injury and Osteoarthritis Outcome Score (KOOS) improved significantly throughout the 12 months for both groups (p